This invention relates to variable impedance devices, and more particularly to variable impedance devices wherein an impedance value such as resistance can be varied stepwise and arbitrarily.
In many prior art variable resistors, the resistance is varied continuously from lower values towards higher values or from higher values towards lower values. There are also variable, resistors such as attenuators for audio equipment, wherein the resistance is varied stepwise from lower values towards higher values or conversely. However, in these devices stepwise variation of a resistance is often accomplished by only complicated arrangements and the resistance cannot be varied arbitrarily when a lever or rotary shaft of the device is operated in one direction only. Also, there is need for a device in which an inductance or capacitance value can be varied in this manner. Furthermore, there is need for a variable impedance device in which an inductance can be made to appear between terminals at one time, a capacitance can be made to appear on another ocassion and a composite value consisting of a capacitance and a resistance can be made to appear on still another occasion.